Equilibrium dialysis and polarographic studies on the binding of molybdate anions with ovalbumin and transfusion gelatin

Abstract

The binding of molybdate ions has been studied with ovalbumin and transfusion gelatin using polarographic and equilibrium dialysis techniques. The intrinsic association constants and the number of sites have been calculated from Scatchard plots. The values of the association constants ( K) have been found to be 3.2 × 10 3 (pH 5.57), 3.06 × 10 3 (pH 7.5) and 2.8 × 10 3 (pH 9.3) for transfusion gelatin and 3.38 × 10 3 (pH 5.57), 3.33 × 10 3 (pH 7.5) and 3.28 × 10 3 (pH 9.3) for ovalbumin. The number of sites available for binding with the molybdate ions is much less than the actual number of cationic groups, which are 10,9, 8 for transfusion gelatin and 8, 7, 6 for ovalbumin at pH-values of 5.57, 7.5 and 9.3 respectively. Statistical effects seem to be more pronounced at lower concentrations and electrostatic effects at higher molybdate ion concentrations.